Device for testing strings for musical instruments.



No. 814,541. PATENTBD MAR. 6, 1906.

0. WVHOGGARD.

DEVICE FOR TESTING STRINGS FOR MUSICAL INSTRUMENTS.

\ APPLICATION FILED JULY 31. 1905.

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No. 814,541. PATENTED MAR. 6, 1906. C. W. HOGGARD. DEVICE FOR TESTINGSTRINGS FOR MUSICAL INSTRUMENTS.

APPLICATION FILED JULY 31 1905.

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WWWM; v I [Ni (911162;. WW WI CHARLES WILLIAM HOGGARD, OF PLUMSTEAD,ENGLAND.

DEVICE FOR TESTING STRINGS FOR MUS ICAL INSTRUMENTS.

Specification of Letters Patent.

Patented March 6, 1 906.

Application filed July 31, 1905. Serial No- 272,032.

To all whmn it may concern:

Be it known that 1, CHARLES WILLIAM HOGGARD, L. R. A. M., a subject ofthe King of Great Britain, and a resident of 37 Herbert road, Plumstead,in the county of Kent, England, have invented a new and useful Devicefor Testing Strings for Musical Instruments, of which the following is aspecification.

My invention relates to an improved de vice for testing the uniformityof ut strings for violins, violoncellos, Violas, andl ike instruments,for which it is important that such strings should be of uniformthickness and quality from end to end of the stretched part and theobjects of my improvements are to test the strings by means of soundsproduced by the vibration of different parts of the stretched stringitself, so that to a sensitive ear any imperfection caused by varyingthickness and character of different parts of the string can be at oncedetected, the length of string having such im erfect parts beingrejected. I attain these 0 jects by the mechanism illustrated in theaccompanying drawings, in which t Figure 1 is a side View of the entirestringtesting device. Fig. 2 is a top view, Fig. 3 an end view, and Fig.4 shows separately an end view of one of the stretching-pulleys.

Similar letters refer to similar parts throughout the several views. 1

a is a rigid frame consisting of two side plates connected by stays ofsufficient length for the string 6, which is to be tested, and made oflight metal, such as aluminium.

c c are feet or supports upon which the frame a is carriedjand d d aretransverse parallel spindles revolving in bearings near the ends of theframe, and e e are pulleys fixed upon the spindles d d between the sidesof the frame a and of considerable diameter and flat transversely orslightly concave at their outer edge, round which the string b to betested can be readily wound, the part to be tested being stretchedbetween the two pulleys e 6. One of the pulleys e is fixed upon itsspindle, and f is a pawl pivoted to one of its sides and near its edgeand engaging with the an ular ratchet-shaped teeth 9 of a 'wheel h, whicturns freely upon the spindle against the side of the pulley e, and theratchet-teeth g are numerous and small, so that the pulley 0 can bereadily turned round to wind up and tighten the string 1) to any desiredextent, the string passing from the upper part of the pulley e to thecorresponding part of the second pulley e, (fixed on the spindle d,)round which it is wound and fastened and which must be held firmly toprevent it from turning. This second pulley e is fixed in any positionby a movable stop sliding in a guide Z on the frame a, so that its endcan be introduced into or withdrawn (by a spring from any one of aseries of holes in the side of the ulley (2, so that when withdrawn itis held back by a pin fitting in a bayonet-joint in the guide I, whilewhen released the pulley is held firmly and prevented from revolving.When the pulley e is being held fast, as described, and the pulley c isturned round, it is evident that the string 1) can be stretched betweenthe two pulleys to any desired extent and then held fast. The string 5to be tested is not, however, stretched directly between the two pulleyse e but on its way between them passes over the upper transverse edgesof two bridges k k, firmly but adjustably fixed near the pulleys e 6,round which the string passes, but at a short distance above them, sothat the string rises somewhat above the peripheries of the pulleys tothe bridges k k and is then stretched over and between the latter in astraight line.

m is a transverse frame having longitudinal flanges n, by which theupper edges of the side frames (1 are stayed firmly together, and thesupports upon which the bridges 7c is are carried are fixed upon theupper surface of brackets upon the inside of the side frames (1 byscrews which pass through the frame m and are screwed into the brackets.The holes for the screws through the supports of the bridges areelongated, so that a certain amount of longitudinal adjustment of thebridge-supports is possible.

The upper inner edges of the flanges n of the plate m have formed uponthem from end. to end dovetailed-shaped grooves, made as true aspossible, in which slides accurately the base of the support of a thirdcare-fullyformed bridge M, (which may be made adjustable in height,)which can therefore be moved from end to end directly but withsufficient friction under the stretched string 6, which touches itlightly.

The lateral edges of the bottom of the adjustably-fixed supports for thebridges k k fit in the ends of the dovetailed grooves, and they areconnected and stayed firmly together by strong rods or bars 0, extendingbe tween them and fixed by nuts 1) upon their screwed ends, which arescrewed up when the exact position of the bridges k ]c has beendetermined.

Upon the corresponding side of both the pulleys e and e is fixed atoothed chain-wheel q q of equal size round which is passed an endlessmetal chain 1 gearing with the teeth, so that when one of the pulleys isturned round (the pulley 6 being set free by the withdrawal of themovable stop from the hole in which it has been engaged) the two pulleysrevolve together without affecting the tension of the string 1),stretched between them, and. a fresh part of the latter can be subjectto test between the two bridges k It. At the same time the independentturning round of the separate outer part of the pulley e for the purposeof stretching the string is not prevented, and when turned to the properpitch the outer part of the pulley e is prevented from turning back bythe spring-pawl Both pulleys and the string can be retained in theposition attained by the stop at Z in the side of the second pulley e.WVhen the pawl is released, the tested string can be taken oil thepulleys.

The exact position of the movable central bridge in relation to the twoend ones can be exactly determined by means of graduated marks upon ascale s or the like upon the guide fixed upon the supports of thebridges k k, and a corresponding mark or pointer on the movable bridge kso that the stretched string may be divided to give any desired musicalinterval between its two parts.

The operation of the apparatus is as follows: The string ba violinstring, for i11- stancewhich is to be tested is wound and fastened uponthe two pulleys or drums e e and is then tightened to the degreerequired by turning the separate outer part of the pulley e, the tensionbeing retained by the springpawl f and the part of the string betweenthe bridges k and 7c being equal to the length of the stretched stringof an ordinary violin. The central bridge I is then moved along theguides in which it moves until the two parts of the string 1) are eitherexactly equal or are divided into the exact proportion to give definiterelative musical tones with the exact intervals when sounded, theprecise position of the central bridge 71: being accurately indi catedupon the scale 8. If after the position has been fixed the two parts aresounded, the notes produced should have an exact relation to each other,(determined by the ear) and if they do not show this exact relation itis obvious that there must be a defect in the thickness or character ofone or other part, and the string so tested is useless for theproduction of perfect intonation when playing. Any part of the stringcan be quickly and easily tested in the way described by turning roundthe two pulleys upon which it is wound and which are connected togetherso that they move simultaneously, as by the chainwheels and chaindescribed. At the same time the string can be stretched to any desiredextent by means of the separate part of the pulley a, round which it iswound.

hat I claim as my invention, and desire to secure by Letters Patent, is

1. In a device for testing the strings of musical instruments, thecombination of a supporting-frame. bridges thereon over which the stringto be tested is adapted to be stretched to the desired tensioncooperating means for stretching said string and moving said stringalong said frame without varying the tension thereof, substantially asdescribed.

2. In a device for testing the strings of musical instruments, thecombination of a supporting-frame, adjustable bridges supported thereby,a scale on the top of said frame, a movable bridge between saidadjustable bridges, cooperating means for stretching the string to betested to the desired tension and moving a new portion of the stringalong said bridges without varying the tension of said string,substantially as described.

3. In a device for testing the strings of musical instruments, thecombination of a supporting-frame, pulleys to which the ends of thestring to be tested are attached, a movable part operatively associatedwith one of said pulleys, whereby the string to be tested may bestretched to and held at the desired tension, a movable stop forlimiting the motion of the other pulley, and means for causing saidpulleys to move simultaneously, substantially as described.

4. In a device for testing the strings of musical instruments, thecombination of a supporting-frame having two parts provided withlongitudinal guides 011 their upper edges, transverse spindles, pulleysfor supporting and moving the string to be tested mounted on saidpulleys, adjustably-fixed transverse bridges located near the ends ofsaid frame, stays connecting said bridges, a movable bridge sliding inthe guides of said frame, and means for connecting said pulleys togetherso that they will revolve simultaneously, substantially as described.

5. In a device for testing the strings of musical instruments, thecombination of a supporting-frame over which the string to be tested isadapted to be stretched, pulleys to which the ends of said string areattached, a movable part operatively associated with one of saidpulleys, whereby the tension of the string may be varied, a movablespringstop adapted to engage the other of said pulleys, and means forconnecting said pulleys together so that they will move simultaneously,substantially as described.

6. In a device for testing the strings of musical instruments, thecombination of a frame, a pulley mounted at one end of said 0nd pulleywith said ratchet-Wheel, substan- 10 frame, and a second pulley mountedat the tially as described. 7 opposite end of said frame, said pulleysbeing In Witness whereof I have hereunto set my adapted to receive theends of the string to hand in the presence of tWo Witnesses.

be tested, a ratchet-Wheel adjacent said first pulley, a spring-pawlcarried by said first pulley cooperating with said ratehet-wheel,Witnesses: a spring-operated stop for said second pulley, ARTHUR E.EDWARDS, and means operatively connecting said sec- ALFRED T. BRATTON.

CHARLES WILLIAM HOGGARD.

